A common sight in any supermarket is a cluster of containers that have been grouped together in some way for sale. For example, one often sees large shrink-wrapped packages in which many single-serving containers have been grouped together to be sold as a unit. These container clusters are often more convenient for a consumer who wishes to buy many drinks at one time. In addition, the cost per container for a consumer is often lower when buying by the product cluster.
To make these container clusters, it is first necessary to arrange containers so that they are in the correct spatial relationship relative to each other. For example, if one wishes to form a container cluster arranged in an array of columns and rows, some way must be found to arrange the containers in such an array in the first place.
In many cases, a conveyor belt conveys a single stream of containers. To form the rows of such an array, it is necessary to divide this single stream into multiple streams, each of which forms a row. Doing this often results in having to change the bottle's velocity vector in some way. A change of velocity is, of course, acceleration. Since force and acceleration are related, this acceleration introduces a force that may topple the bottles.